Removal of WeakMap/WeakSet clear

Jason Orendorff jason.orendorff at
Sat Nov 29 09:13:13 PST 2014

On Thu, Nov 27, 2014 at 8:58 AM, Andrea Giammarchi
<andrea.giammarchi at> wrote:
> On Thu, Nov 27, 2014 at 2:44 PM, Andreas Rossberg <rossberg at>
> wrote:
>> Well, there is no functionally correct polyfill for WeakMaps that is
>> actually weak, regardless of .clear.
> Please bear with me so I understand your point: if you have `o1` and `o2`
> and ` = o2;`, wouldn't `o2` be "free" once `o1` is not referenced
> anymore ?

Yes, but consider the other way around: o1 is still referenced, but
the WeakMap is not.

Under a polyfill, o2 would still be kept alive, even though per spec
there's not supposed to be any way to access it.


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